Friday, April 11, 2014 at 3:30pm Frank H. T. Rhodes Hall, 655 CAM Colloquium: Steven W. Shaw (Michigan St.) - Coupled Pendulums as Vibration Absorbers: how nonlinear dynamics will help improve automotive fuel economy Centrifugal pendulum vibration absorbers consist of a set of masses suspended from a spinning rotor, tuned so that they oscillate and attenuate torsional fluctuations of the rotor. These absorbers are being developed to enable efficient, low-speed operation of automotive engines, thereby improving fuel economy. Due to spatial and inertial limitations in engines, the pendulums must function well into their nonlinear dynamic range, which can be modified by the design of the suspension mechanism, an idea that goes back to the pendulum clocks of Huygens. In order to develop absorber systems that achieve optimal performance, one must understand the rich behavior of this dynamical system, including symmetry-related instabilities that arise from the coupling of the pendulums through the rotor. In this presentation I will summarize the history of pendulum absorbers and then describe modeling, perturbation analysis, bifurcation studies, simulations, experiments, engine tests, and current progress towards mass production. Acknowledgements: This work has been carried out jointly with MSU Professors Alan Haddow and Brian Feeny, several current and former MSU graduate students, and industrial collaborators from Ford, Honda, and, most prominently and consistently, Dr. Bruce Geist from Chrysler. Our current work in this area is funded by an NSF GOALI grant and by Chrysler.